Brain abscess caused by Listeria monocytogenes: a case report and literature review

Listeria monocytogenes (L. monocytogenes) is an opportunistic facultative anaerobic pathogen that is widely distributed in nature. Brain infection (meningitis and meningoencephalitis) and bacteremia are common clinical manifestations of listeriosis in elderly and immunocompromised individuals. Brain abscesses caused by L. monocytogenes are extremely rare. In this study, we describe a case of an older male who with a brain abscess caused by Listeria infection.

We report a case of a 59-year-old male who was once diagnosed with acute cerebral infarction. The diagnose was changed after needle biopsy of the abscess and culture of L. monocytogenes. The patient was first empirically used the broad-spectrum antibiotic meropenem for 12 days (2 g Q8 h) until culture results were available, and then switched to oral trimethoprim/sulfamethoxazole 160/800 mg/12 h for further 2 weeks. The symptoms of slurred speech, numbness and impaired muscle strength of the right leg improved. Computed tomography (CT) and magnetic resonance imaging (MRI) examination were performed 2 weeks after operation showed smaller abscess and reduced perifocal edema. The patient was continued oral trimethoprim/sulfamethoxazole for 8 weeks. The remaining right arm dysfunction recovered. After six months, the patient had returned to normal daily activities and only exhibited weakness of the right fingers.

Brain abscess caused by L. monocytogenes should be considered in patients who have risk factors for listeriosis. Pathogen infection, including with Listeria monocytogenes, should be taken into account when patients with impaired immune function exhibit hemiplegia and aphasia. Listeria infection should also be considered in immunocompetent patients. Performing needle biopsy or lesion resection and starting antibiotic therapy according to drug susceptibility testing in the early stage is key to treating this kind of disease.